1. Technical Field
The present disclosure relates to secondary battery systems, and more particularly relates to charge and discharge control of a secondary battery system including a secondary battery (lithium-ion secondary battery) having an electrode body impregnated with an electrolyte containing lithium ions.
2. Description of Related Art
In recent years, a secondary battery system incorporating as a battery a lithium-ion secondary battery is widespread. In such a secondary battery system, an electrolyte of the battery can be solidified (frozen) under very low temperature environment. When the electrolyte is solidified, it is desirable to restrict charge and discharge of the battery in order to protect the battery. For example, in a motor vehicle disclosed in Japanese Patent Application Publication No. 2013-183523, a relay is opened at temperatures equal to or below a freezing point of the electrolyte so as to electrically disconnect the battery from an external power supply and electric loads.